2 files changed, 209 insertions, 41 deletions

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index b9ce24129070..ba25832a756c 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -39,6 +39,7 @@
 #include <linux/quotaops.h>
 #include <linux/string.h>
 #include <linux/slab.h>
+#include <linux/falloc.h>
 #include <linux/ext4_fs_extents.h>
 #include <asm/uaccess.h>
 
@@ -282,7 +283,7 @@ static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
                 } else if (path->p_ext) {
                         ext_debug("  %d:%d:%llu ",
                                   le32_to_cpu(path->p_ext->ee_block),
-                                  le16_to_cpu(path->p_ext->ee_len),
+                                  ext4_ext_get_actual_len(path->p_ext),
                                   ext_pblock(path->p_ext));
                 } else
                         ext_debug("  []");
@@ -305,7 +306,7 @@ static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 
         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
                 ext_debug("%d:%d:%llu ", le32_to_cpu(ex->ee_block),
-                          le16_to_cpu(ex->ee_len), ext_pblock(ex));
+                          ext4_ext_get_actual_len(ex), ext_pblock(ex));
         }
         ext_debug("\n");
 }
@@ -425,7 +426,7 @@ ext4_ext_binsearch(struct inode *inode, struct ext4_ext_path *path, int block)
         ext_debug("  -> %d:%llu:%d ",
                         le32_to_cpu(path->p_ext->ee_block),
                         ext_pblock(path->p_ext),
-                        le16_to_cpu(path->p_ext->ee_len));
+                        ext4_ext_get_actual_len(path->p_ext));
 
 #ifdef CHECK_BINSEARCH
         {
@@ -686,7 +687,7 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode,
                 ext_debug("move %d:%llu:%d in new leaf %llu\n",
                                 le32_to_cpu(path[depth].p_ext->ee_block),
                                 ext_pblock(path[depth].p_ext),
-                                le16_to_cpu(path[depth].p_ext->ee_len),
+                                ext4_ext_get_actual_len(path[depth].p_ext),
                                 newblock);
                 /*memmove(ex++, path[depth].p_ext++,
                                 sizeof(struct ext4_extent));
@@ -1106,7 +1107,19 @@ static int
 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
                                 struct ext4_extent *ex2)
 {
-        if (le32_to_cpu(ex1->ee_block) + le16_to_cpu(ex1->ee_len) !=
+        unsigned short ext1_ee_len, ext2_ee_len;
+
+        /*
+         * Make sure that either both extents are uninitialized, or
+         * both are _not_.
+         */
+        if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2))
+                return 0;
+
+        ext1_ee_len = ext4_ext_get_actual_len(ex1);
+        ext2_ee_len = ext4_ext_get_actual_len(ex2);
+
+        if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
                         le32_to_cpu(ex2->ee_block))
                 return 0;
 
@@ -1115,14 +1128,14 @@ ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
          * as an RO_COMPAT feature, refuse to merge to extents if
          * this can result in the top bit of ee_len being set.
          */
-        if (le16_to_cpu(ex1->ee_len) + le16_to_cpu(ex2->ee_len) > EXT_MAX_LEN)
+        if (ext1_ee_len + ext2_ee_len > EXT_MAX_LEN)
                 return 0;
 #ifdef AGGRESSIVE_TEST
         if (le16_to_cpu(ex1->ee_len) >= 4)
                 return 0;
 #endif
 
-        if (ext_pblock(ex1) + le16_to_cpu(ex1->ee_len) == ext_pblock(ex2))
+        if (ext_pblock(ex1) + ext1_ee_len == ext_pblock(ex2))
                 return 1;
         return 0;
 }
@@ -1144,7 +1157,7 @@ unsigned int ext4_ext_check_overlap(struct inode *inode,
         unsigned int ret = 0;
 
         b1 = le32_to_cpu(newext->ee_block);
-        len1 = le16_to_cpu(newext->ee_len);
+        len1 = ext4_ext_get_actual_len(newext);
         depth = ext_depth(inode);
         if (!path[depth].p_ext)
                 goto out;
@@ -1191,8 +1204,9 @@ int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
         struct ext4_extent *nearex; /* nearest extent */
         struct ext4_ext_path *npath = NULL;
         int depth, len, err, next;
+        unsigned uninitialized = 0;
 
-        BUG_ON(newext->ee_len == 0);
+        BUG_ON(ext4_ext_get_actual_len(newext) == 0);
         depth = ext_depth(inode);
         ex = path[depth].p_ext;
         BUG_ON(path[depth].p_hdr == NULL);
@@ -1200,14 +1214,24 @@ int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
         /* try to insert block into found extent and return */
         if (ex && ext4_can_extents_be_merged(inode, ex, newext)) {
                 ext_debug("append %d block to %d:%d (from %llu)\n",
-                                le16_to_cpu(newext->ee_len),
+                                ext4_ext_get_actual_len(newext),
                                 le32_to_cpu(ex->ee_block),
-                                le16_to_cpu(ex->ee_len), ext_pblock(ex));
+                                ext4_ext_get_actual_len(ex), ext_pblock(ex));
                 err = ext4_ext_get_access(handle, inode, path + depth);
                 if (err)
                         return err;
-                ex->ee_len = cpu_to_le16(le16_to_cpu(ex->ee_len)
-                                         + le16_to_cpu(newext->ee_len));
+
+                /*
+                 * ext4_can_extents_be_merged should have checked that either
+                 * both extents are uninitialized, or both aren't. Thus we
+                 * need to check only one of them here.
+                 */
+                if (ext4_ext_is_uninitialized(ex))
+                        uninitialized = 1;
+                ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
+                                        + ext4_ext_get_actual_len(newext));
+                if (uninitialized)
+                        ext4_ext_mark_uninitialized(ex);
                 eh = path[depth].p_hdr;
                 nearex = ex;
                 goto merge;
@@ -1263,7 +1287,7 @@ has_space:
                 ext_debug("first extent in the leaf: %d:%llu:%d\n",
                                 le32_to_cpu(newext->ee_block),
                                 ext_pblock(newext),
-                                le16_to_cpu(newext->ee_len));
+                                ext4_ext_get_actual_len(newext));
                 path[depth].p_ext = EXT_FIRST_EXTENT(eh);
         } else if (le32_to_cpu(newext->ee_block)
                            > le32_to_cpu(nearex->ee_block)) {
@@ -1276,7 +1300,7 @@ has_space:
                                         "move %d from 0x%p to 0x%p\n",
                                         le32_to_cpu(newext->ee_block),
                                         ext_pblock(newext),
-                                        le16_to_cpu(newext->ee_len),
+                                        ext4_ext_get_actual_len(newext),
                                         nearex, len, nearex + 1, nearex + 2);
                         memmove(nearex + 2, nearex + 1, len);
                 }
@@ -1289,7 +1313,7 @@ has_space:
                                 "move %d from 0x%p to 0x%p\n",
                                 le32_to_cpu(newext->ee_block),
                                 ext_pblock(newext),
-                                le16_to_cpu(newext->ee_len),
+                                ext4_ext_get_actual_len(newext),
                                 nearex, len, nearex + 1, nearex + 2);
                 memmove(nearex + 1, nearex, len);
                 path[depth].p_ext = nearex;
@@ -1308,8 +1332,13 @@ merge:
                 if (!ext4_can_extents_be_merged(inode, nearex, nearex + 1))
                         break;
                 /* merge with next extent! */
-                nearex->ee_len = cpu_to_le16(le16_to_cpu(nearex->ee_len)
-                                             + le16_to_cpu(nearex[1].ee_len));
+                if (ext4_ext_is_uninitialized(nearex))
+                        uninitialized = 1;
+                nearex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(nearex)
+                                        + ext4_ext_get_actual_len(nearex + 1));
+                if (uninitialized)
+                        ext4_ext_mark_uninitialized(nearex);
+
                 if (nearex + 1 < EXT_LAST_EXTENT(eh)) {
                         len = (EXT_LAST_EXTENT(eh) - nearex - 1)
                                         * sizeof(struct ext4_extent);
@@ -1379,8 +1408,8 @@ int ext4_ext_walk_space(struct inode *inode, unsigned long block,
                         end = le32_to_cpu(ex->ee_block);
                         if (block + num < end)
                                 end = block + num;
-                } else if (block >=
-                             le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len)) {
+                } else if (block >= le32_to_cpu(ex->ee_block)
+                                        + ext4_ext_get_actual_len(ex)) {
                         /* need to allocate space after found extent */
                         start = block;
                         end = block + num;
@@ -1392,7 +1421,8 @@ int ext4_ext_walk_space(struct inode *inode, unsigned long block,
                          * by found extent
                          */
                         start = block;
-                        end = le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len);
+                        end = le32_to_cpu(ex->ee_block)
+                                + ext4_ext_get_actual_len(ex);
                         if (block + num < end)
                                 end = block + num;
                         exists = 1;
@@ -1408,7 +1438,7 @@ int ext4_ext_walk_space(struct inode *inode, unsigned long block,
                         cbex.ec_type = EXT4_EXT_CACHE_GAP;
                 } else {
                         cbex.ec_block = le32_to_cpu(ex->ee_block);
-                        cbex.ec_len = le16_to_cpu(ex->ee_len);
+                        cbex.ec_len = ext4_ext_get_actual_len(ex);
                         cbex.ec_start = ext_pblock(ex);
                         cbex.ec_type = EXT4_EXT_CACHE_EXTENT;
                 }
@@ -1481,15 +1511,15 @@ ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
                 ext_debug("cache gap(before): %lu [%lu:%lu]",
                                 (unsigned long) block,
                                 (unsigned long) le32_to_cpu(ex->ee_block),
-                                (unsigned long) le16_to_cpu(ex->ee_len));
+                                (unsigned long) ext4_ext_get_actual_len(ex));
         } else if (block >= le32_to_cpu(ex->ee_block)
-                            + le16_to_cpu(ex->ee_len)) {
+                        + ext4_ext_get_actual_len(ex)) {
                 lblock = le32_to_cpu(ex->ee_block)
-                         + le16_to_cpu(ex->ee_len);
+                        + ext4_ext_get_actual_len(ex);
                 len = ext4_ext_next_allocated_block(path);
                 ext_debug("cache gap(after): [%lu:%lu] %lu",
                                 (unsigned long) le32_to_cpu(ex->ee_block),
-                                (unsigned long) le16_to_cpu(ex->ee_len),
+                                (unsigned long) ext4_ext_get_actual_len(ex),
                                 (unsigned long) block);
                 BUG_ON(len == lblock);
                 len = len - lblock;
@@ -1619,12 +1649,12 @@ static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
                                 unsigned long from, unsigned long to)
 {
         struct buffer_head *bh;
+        unsigned short ee_len =  ext4_ext_get_actual_len(ex);
         int i;
 
 #ifdef EXTENTS_STATS
         {
                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
-                unsigned short ee_len =  le16_to_cpu(ex->ee_len);
                 spin_lock(&sbi->s_ext_stats_lock);
                 sbi->s_ext_blocks += ee_len;
                 sbi->s_ext_extents++;
@@ -1638,12 +1668,12 @@ static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
         }
 #endif
         if (from >= le32_to_cpu(ex->ee_block)
-            && to == le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - 1) {
+            && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
                 /* tail removal */
                 unsigned long num;
                 ext4_fsblk_t start;
-                num = le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - from;
-                start = ext_pblock(ex) + le16_to_cpu(ex->ee_len) - num;
+                num = le32_to_cpu(ex->ee_block) + ee_len - from;
+                start = ext_pblock(ex) + ee_len - num;
                 ext_debug("free last %lu blocks starting %llu\n", num, start);
                 for (i = 0; i < num; i++) {
                         bh = sb_find_get_block(inode->i_sb, start + i);
@@ -1651,12 +1681,12 @@ static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
                 }
                 ext4_free_blocks(handle, inode, start, num);
         } else if (from == le32_to_cpu(ex->ee_block)
-                   && to <= le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - 1) {
+                   && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) {
                 printk("strange request: removal %lu-%lu from %u:%u\n",
-                       from, to, le32_to_cpu(ex->ee_block), le16_to_cpu(ex->ee_len));
+                        from, to, le32_to_cpu(ex->ee_block), ee_len);
         } else {
                 printk("strange request: removal(2) %lu-%lu from %u:%u\n",
-                       from, to, le32_to_cpu(ex->ee_block), le16_to_cpu(ex->ee_len));
+                        from, to, le32_to_cpu(ex->ee_block), ee_len);
         }
         return 0;
 }
@@ -1671,6 +1701,7 @@ ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
         unsigned a, b, block, num;
         unsigned long ex_ee_block;
         unsigned short ex_ee_len;
+        unsigned uninitialized = 0;
         struct ext4_extent *ex;
 
         ext_debug("truncate since %lu in leaf\n", start);
@@ -1685,7 +1716,9 @@ ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
         ex = EXT_LAST_EXTENT(eh);
 
         ex_ee_block = le32_to_cpu(ex->ee_block);
-        ex_ee_len = le16_to_cpu(ex->ee_len);
+        if (ext4_ext_is_uninitialized(ex))
+                uninitialized = 1;
+        ex_ee_len = ext4_ext_get_actual_len(ex);
 
         while (ex >= EXT_FIRST_EXTENT(eh) &&
                         ex_ee_block + ex_ee_len > start) {
@@ -1753,6 +1786,8 @@ ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
 
                 ex->ee_block = cpu_to_le32(block);
                 ex->ee_len = cpu_to_le16(num);
+                if (uninitialized)
+                        ext4_ext_mark_uninitialized(ex);
 
                 err = ext4_ext_dirty(handle, inode, path + depth);
                 if (err)
@@ -1762,7 +1797,7 @@ ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
                                 ext_pblock(ex));
                 ex--;
                 ex_ee_block = le32_to_cpu(ex->ee_block);
-                ex_ee_len = le16_to_cpu(ex->ee_len);
+                ex_ee_len = ext4_ext_get_actual_len(ex);
         }
 
         if (correct_index && eh->eh_entries)
@@ -2038,7 +2073,7 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
         if (ex) {
                 unsigned long ee_block = le32_to_cpu(ex->ee_block);
                 ext4_fsblk_t ee_start = ext_pblock(ex);
-                unsigned short ee_len  = le16_to_cpu(ex->ee_len);
+                unsigned short ee_len;
 
                 /*
                  * Allow future support for preallocated extents to be added
@@ -2046,8 +2081,9 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
                  * Uninitialized extents are treated as holes, except that
                  * we avoid (fail) allocating new blocks during a write.
                  */
-                if (ee_len > EXT_MAX_LEN)
+                if (le16_to_cpu(ex->ee_len) > EXT_MAX_LEN)
                         goto out2;
+                ee_len = ext4_ext_get_actual_len(ex);
                 /* if found extent covers block, simply return it */
                 if (iblock >= ee_block && iblock < ee_block + ee_len) {
                         newblock = iblock - ee_block + ee_start;
@@ -2055,8 +2091,11 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
                         allocated = ee_len - (iblock - ee_block);
                         ext_debug("%d fit into %lu:%d -> %llu\n", (int) iblock,
                                         ee_block, ee_len, newblock);
-                        ext4_ext_put_in_cache(inode, ee_block, ee_len,
-                                                ee_start, EXT4_EXT_CACHE_EXTENT);
+                        /* Do not put uninitialized extent in the cache */
+                        if (!ext4_ext_is_uninitialized(ex))
+                                ext4_ext_put_in_cache(inode, ee_block,
+                                                        ee_len, ee_start,
+                                                        EXT4_EXT_CACHE_EXTENT);
                         goto out;
                 }
         }
@@ -2098,6 +2137,8 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
         /* try to insert new extent into found leaf and return */
         ext4_ext_store_pblock(&newex, newblock);
         newex.ee_len = cpu_to_le16(allocated);
+        if (create == EXT4_CREATE_UNINITIALIZED_EXT)  /* Mark uninitialized */
+                ext4_ext_mark_uninitialized(&newex);
         err = ext4_ext_insert_extent(handle, inode, path, &newex);
         if (err) {
                 /* free data blocks we just allocated */
@@ -2113,8 +2154,10 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
         newblock = ext_pblock(&newex);
         __set_bit(BH_New, &bh_result->b_state);
 
-        ext4_ext_put_in_cache(inode, iblock, allocated, newblock,
-                                EXT4_EXT_CACHE_EXTENT);
+        /* Cache only when it is _not_ an uninitialized extent */
+        if (create != EXT4_CREATE_UNINITIALIZED_EXT)
+                ext4_ext_put_in_cache(inode, iblock, allocated, newblock,
+                                                EXT4_EXT_CACHE_EXTENT);
 out:
         if (allocated > max_blocks)
                 allocated = max_blocks;
@@ -2217,3 +2260,127 @@ int ext4_ext_writepage_trans_blocks(struct inode *inode, int num)
 
         return needed;
 }
+
+/*
+ * preallocate space for a file. This implements ext4's fallocate inode
+ * operation, which gets called from sys_fallocate system call.
+ * For block-mapped files, posix_fallocate should fall back to the method
+ * of writing zeroes to the required new blocks (the same behavior which is
+ * expected for file systems which do not support fallocate() system call).
+ */
+long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len)
+{
+        handle_t *handle;
+        ext4_fsblk_t block, max_blocks;
+        ext4_fsblk_t nblocks = 0;
+        int ret = 0;
+        int ret2 = 0;
+        int retries = 0;
+        struct buffer_head map_bh;
+        unsigned int credits, blkbits = inode->i_blkbits;
+
+        /*
+         * currently supporting (pre)allocate mode for extent-based
+         * files _only_
+         */
+        if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
+                return -EOPNOTSUPP;
+
+        /* preallocation to directories is currently not supported */
+        if (S_ISDIR(inode->i_mode))
+                return -ENODEV;
+
+        block = offset >> blkbits;
+        max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
+                        - block;
+
+        /*
+         * credits to insert 1 extent into extent tree + buffers to be able to
+         * modify 1 super block, 1 block bitmap and 1 group descriptor.
+         */
+        credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + 3;
+retry:
+        while (ret >= 0 && ret < max_blocks) {
+                block = block + ret;
+                max_blocks = max_blocks - ret;
+                handle = ext4_journal_start(inode, credits);
+                if (IS_ERR(handle)) {
+                        ret = PTR_ERR(handle);
+                        break;
+                }
+
+                ret = ext4_ext_get_blocks(handle, inode, block,
+                                          max_blocks, &map_bh,
+                                          EXT4_CREATE_UNINITIALIZED_EXT, 0);
+                WARN_ON(!ret);
+                if (!ret) {
+                        ext4_error(inode->i_sb, "ext4_fallocate",
+                                   "ext4_ext_get_blocks returned 0! inode#%lu"
+                                   ", block=%llu, max_blocks=%llu",
+                                   inode->i_ino, block, max_blocks);
+                        ret = -EIO;
+                        ext4_mark_inode_dirty(handle, inode);
+                        ret2 = ext4_journal_stop(handle);
+                        break;
+                }
+                if (ret > 0) {
+                        /* check wrap through sign-bit/zero here */
+                        if ((block + ret) < 0 || (block + ret) < block) {
+                                ret = -EIO;
+                                ext4_mark_inode_dirty(handle, inode);
+                                ret2 = ext4_journal_stop(handle);
+                                break;
+                        }
+                        if (buffer_new(&map_bh) && ((block + ret) >
+                            (EXT4_BLOCK_ALIGN(i_size_read(inode), blkbits)
+                            >> blkbits)))
+                                        nblocks = nblocks + ret;
+                }
+
+                /* Update ctime if new blocks get allocated */
+                if (nblocks) {
+                        struct timespec now;
+
+                        now = current_fs_time(inode->i_sb);
+                        if (!timespec_equal(&inode->i_ctime, &now))
+                                inode->i_ctime = now;
+                }
+
+                ext4_mark_inode_dirty(handle, inode);
+                ret2 = ext4_journal_stop(handle);
+                if (ret2)
+                        break;
+        }
+
+        if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+                goto retry;
+
+        /*
+         * Time to update the file size.
+         * Update only when preallocation was requested beyond the file size.
+         */
+        if (!(mode & FALLOC_FL_KEEP_SIZE) &&
+            (offset + len) > i_size_read(inode)) {
+                if (ret > 0) {
+                        /*
+                         * if no error, we assume preallocation succeeded
+                         * completely
+                         */
+                        mutex_lock(&inode->i_mutex);
+                        i_size_write(inode, offset + len);
+                        EXT4_I(inode)->i_disksize = i_size_read(inode);
+                        mutex_unlock(&inode->i_mutex);
+                } else if (ret < 0 && nblocks) {
+                        /* Handle partial allocation scenario */
+                        loff_t newsize;
+
+                        mutex_lock(&inode->i_mutex);
+                        newsize  = (nblocks << blkbits) + i_size_read(inode);
+                        i_size_write(inode, EXT4_BLOCK_ALIGN(newsize, blkbits));
+                        EXT4_I(inode)->i_disksize = i_size_read(inode);
+                        mutex_unlock(&inode->i_mutex);
+                }
+        }
+
+        return ret > 0 ? ret2 : ret;
+}
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index d4c8186aed64..1a81cd66d63b 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -134,5 +134,6 @@ const struct inode_operations ext4_file_inode_operations = {
         .removexattr    = generic_removexattr,
 #endif
         .permission     = ext4_permission,
+        .fallocate      = ext4_fallocate,
 };